The present invention relates to a new and distinct cultivar of Koelreuteria, known commonly as Golden Rain Tree, which is grown as an ornamental plant for use in the landscape. The new cultivar is known botanically as Koelreuteria paniculata and will be referred to hereinafter by the cultivar name ‘CORAL SUN’.
Koelreuteria paniculata is widely grown and used as a small to medium sized tree in the landscape. There are no cultivars of Koelreuteria paniculata known to the inventor. Plants of Koelreuteria paniculata in commerce are considered to be plants of the species itself. Plants of Koelreuteria paniculata may be raised from seed, and the resulting seedlings are generally sufficiently uniform for growing on into finished plants. Alternatively, seedlings of sufficient vigor may be grafted onto rootstocks which are themselves plants of Koelreuteria paniculata. 
In 1993, the inventor discovered ‘CORAL SUN’ as a single whole plant in a bed of seedlings of Koelreuteria paniculata which had been raised by the inventor at the inventor's nursery in Boskoop, The Netherlands. Typically, the emerging leaves on young seedlings of Koelreuteria paniculata are orange-red in color, which soon changes to mid green as the leaves expand and mature. The inventor observed that the emerging foliage of the single seedling ‘CORAL SUN’ remained orange-red in color even as the plants grew through the spring. In addition, all the leaves of the single seedling ‘CORAL SUN’ exhibited striking bright red petioles. As the single seedling ‘CORAL SUN’ grew on into summer, the foliage turned to light green (lighter than the typical mid-green of the summer growth of the species). In addition, the red coloration of the petioles persisted and became yet more striking against the green summer foliage.
The inventor isolated and observed the single seedling ‘CORAL SUN’ from 1993 until 1996. In 1996, the inventor took portions of budwood from the single three year old seedling ‘CORAL SUN’ and grafted same onto rootstocks of Koelreuteria paniculata. The inventor observed all the resulting grafted progeny for three years and found that the characteristics of orange-red new spring growth and bright red petioles were stable and persistent. The inventor has determined that ‘CORAL SUN’ reproduces true to type in successive generations of asexual propagation.
‘CORAL SUN’ is most closely resembled by its species which is also the parentage. In comparison, ‘CORAL SUN’ and the species Koelreuteria paniculata appear as follows:
The spring foliage growth of the species Koelreuteria paniculata emerges with an orange-red coloration and soon turns to mid green, whereas the foliage of ‘CORAL SUN’ both emerges and persists orange-red into summer and also carries bright red petioles.
The summer foliage growth of the species Koelreuteria paniculata is mid-green in coloration, whereas the summer foliage of ‘CORAL SUN’ is light green in coloration.
A prominent and valued characteristic of Koelreuteria paniculata is the golden yellow color of the fall foliage. In this respect, ‘CORAL SUN’ is indistinct from plants of the species Koelreuteria paniculata. 
An application for a grant of European Community Plant Breeders Rights for ‘CORAL SUN’ was filed by the inventors on Sep. 14, 2004, Application Number 2004/1713.